Coated iron and its application prospect

Preface

With the change of technology development, consumption concept and fashion, the competition between metal, plastic, paper and glass is becoming more and more intense in the packaging materials. And metal packaging material to sealed good, hard texture, good elasticity, good light resistance, air resistance good characteristics, in the field of packaging has always played a an important role, especially for meat, vegetables and other products, metal containers is still the first choice. Tin plate as an important part of the metal packaging materials, in the food, beverage, aerosol cans and chemical tanks and other fields have an important role. But due to the tin as the main strategic resources, the price is more expensive and increasing depletion of resources. Therefore, chrome iron, iron coated and powder electrophoresis products as tin plate and low tin alternative products, more and more people attention.

Production process and product characteristics of 2 coated iron

Production technology of 2.1 coated iron

Coated iron is in cold rolled steel sheet (usually roll sheet) / iron chrome on both sides of the cover (bonding) on top of the multilayer polyester composite thin films (thickness of about 20 to 25 m), two characteristics of a combination of plastic film and sheet metal metal functional materials. Film theory can be directly used in iron cold-rolled steel sheet, namely iron coated blank. Color film blank film technology for the Chinese unique technology, however, blank coated iron can weld of the tank body is easy to produce rust and adhesive force is not in prison; in the US, Europe and Japan, technology of coated iron with iron chrome TFs as substrate, that is not empty iron coated. The fastness of the organic film is very high, which is mainly due to the presence of a layer of chromium oxide film on the surface of TFS products, and the organic film in the form of hydrogen bond together, as shown in figure 1. Figure 2 for the direct and ECCS plating section of the film covering the operation of the line.

Fig. 1 Schematic diagram of TFS substrate and organic film

Fig. 2 the operation line of the thin film layer which is connected with the plating section of ECCS.

1- uncoiler; 2- loop; 3-ECCS segment; 5- loop; 6- coating wax; 7- coiler

At present, there are two kinds of film covering technology: one is under high temperature and high pressure extrusion process. Using high temperature tectorial membrane and acute cold heavy crystallization technology, organic film coating fastness high (Europe and the United States and Japan adopt this technology); the second is bonding process, using low temperature bonding, the bonding fastness than at high pressure and high temperature.

2.2 coated iron product features

With the coating iron (i.e. coated printed tinplate (Du Getie)) compared with iron coated with the following features:

(1) with a good rust, decoration, heat insulation, shock absorption and other functions, in particular, resistance to stamping, corrosion resistance is the coating iron can not be compared. Because of the iron coated covered (adhesive) thin film multilayer polyester composite film and its barrier corrosive media penetration ability close to "completely repression". For tomato sauce pot, two cans of packaging, plastic coated iron is an ideal material. There is contradiction between the corrosion resistance and adhesion of coating iron.

(2) surface pinholes less dense, and can do a variety of processing in the film, such as marking, laser processing (compared with coating). For the two cold rolled coated iron (foreign also known as "Ma Nai"), it has excellent mechanical properties, high tensile strength. Table 1 for two times and two times of cold rolled iron coated ordinary tinplate performance comparison.

Table 1 two times and two times of cold rolled iron coated ordinary tinplate performance comparison

Visible from the table L, the hardness of the DR-8 hardness of the horse is 10%, while the ordinary plate is 3%. According to reports in the literature, Manet in the reason of high hardness, extension is good, the key is in the steel by vacuum smelting, steel in some non metal elements (including carbon) content and some metal elements content decreased (10 ~ 5 grades).

(3) high production efficiency, energy consumption and low material cost. Iron coated surface for thermal plastic resin film, polyethylene Terephalate (PET) on behalf of polyester and polypropylene (PP) is a representative of the resin using the best, about film temperature only 70 DEG C, and no internal coated with printing, production efficiency and energy consumption are more ideal; in addition, coated iron plate without in material and the bottom of the Maguchi Tetsusaku, this in the tinplate prices soaring and resources shortage situation, the cost advantage is obvious.

(4) is conducive to environmental protection. The iron coatings coating based on epoxy resin, coating bottom paint, white paint, coating, acrylic and polyester resin. Thermal curing and UV curable (UV) of, but the printing ink must be matching with paint in order to guarantee the ink color and adhesion of printing ink. Due to the coatings currently used in organic polymer adding curing agent, plasticizer, toner and other ingredients, dissolved in the solvent and thinner, so printing factory still exist environmental problems to be solved. In addition, the tomato sauce pot, deep red two cans, etc., paint iron is still not stable enough. While the surface of the thermoplastic resin film coated iron in the production process without a large amount of solvent waste gas discharge, is conducive to environmental protection.

3 the development of plastic coated iron

After 1990s, as one of the tinplate substitutes TFS products have been widely used in the United States and japan. Its main purpose: crown caps and four screw cap; three piece cans, the top cover and the bottom of the shallow red tank; cooking oil cans, seasoning cans; the shape of the solid food, tea, detergents and other ordinary container; engine fuel oil, paint, paint cans and other. TFs product, but there are two shortcomings: one is the product of both sides shall be coated with protective coating in order to use, and printing and coating process on the environment and human caused very serious benzene pollution; second, some paint there is difficult to avoid the minimal residual affect human health.

Therefore, in late 1980s, Japan successfully produced by plating chromium iron as iron coated substrate. However, the product can not be deep in the beginning of the introduction of deep drawing, and DI tank cost gap is larger, and the market demand is limited, so did not get a wide range of applications. At present, this technology has been the perfect solution, and the advantages of coated iron has been widely recognized by users. Rapid increase of coated iron production. Currently, Japan has coated iron production line 5, Toyo kohan company 3, Nippon Steel Corporation 2 and JFE company 1, capacity for a total of 60 million T / a. 2005, Japan's actual production of coated iron was 490 thousand TFS, accounting for 60% of t production. From the beginning of the 1990s, Germany, Britain, the United States, France and other countries are successfully developed which can completely replace the tin coated iron, in the total consumption of tin plate occupies a large proportion. With the shortage of tin resources and harsh environmental requirements, forcing the rapid development of coated iron in recent years. Table 2005 in early 2 Asia Europe two film coated iron production.

Table two in Asia and Europe at the beginning of 22005 film coated iron production (unit: million tons)

At present, China's coated iron production in the initial stage, a total of two companies: Wuxi, a private-equity firm, has three production lines, with cold-rolled steel sheet coated substrate, with an adhesive production process, with an annual output of 2 million tons, production line speed 80m / min, the film and the substrate bonding fastness than foreign countries; the second is Shanghai Desheng Lianxing company in 1998, the introduction of a coated iron production line, although the product quality and appearance are better than the same type of three pieces of beverage cans products, but because the cost is too high, no competition ability, the production line from the introduction to the now failed to effectively started. It can be said that the current market needs of the TFS substrate coated iron does not have the ability to domestic. With domestic fastest, specifications of the thinnest and most advanced technology of iron chrome dedicated production line of Baosteel cold-rolled sheet plant, with coated with chromium iron substrate by high temperature and high pressure extrusion process for producing coated iron, which is discussed coated iron production line investment and construction plans.

With the increasingly fierce competition in the food packaging materials, canning industry use steel base metal material positive reduction thin development trend. The second cold rolling technology can reduce the thickness of cold rolled plate, improve the utilization rate of per ton steel, so as to achieve the purpose of reducing the cost of, so as to improve the competitiveness of the steel tank. At present, Baosteel cold-rolled sheet plant has two times the cold rolling technology, the thickness of the product is 0.15 ~ 0.36mm, the most thin can reach 0.10mm. And foreign users use specifications generally to be much thinner than domestic users, now developed countries has the thickness of 0.07% ~ 0.12 mm thin plate making barrels, tanks. Baosteel two cold rolled products foreign market share has reached more than 20%, and in the growing. For the secondary cold rolled coated iron, due to using food to adapt to the situation of two cans of increasing, colas (Corus) group and crown (crown) canning company cooperation, joint study of the adaptability of the tectorial membrane secondary cold rolled sheet with the existing equipment. In France, Lorraine sheet factory as the representative, has produced the excellent elongation of the secondary cold rolling of iron coated, very suitable for two pieces of stamping jar and lid.

Current situation and Prospect of the application of 4 coated iron at home and abroad

At present, the iron coated in stamping jar DRD, cupping Di, two pieces of tank, special-shaped cans, EOE (easy opened end and easy tear are very good application prospects cover packaging materials market in the easy Peeled end), this also for canned food, drinks, oil and chemical industry, daily chemical, medical and health industry provides personalized, fashion consumption concept of packaging materials.

In the overseas market for coated iron, mostly not empty iron coated, coated iron pot can be shaped in the dry, without excess lubricant, avoid by clean lubricant produced large quantities of waste water and pollution of the environment. Therefore, the DRD tank (and every kind of stamping punching cupping DI) become more and more popular. For example: the polyethylene of phthalates (PET) and polypropylene (PP) coatings of coated iron can be used for making bottle cap, DRD cans and spray valve cover; using polyester film coated iron has excellent processing adhesion and corrosion resisting and processing, suitable for processing large quantity and loading of high corrosive materials deep drawing tank and tank welding. At the same time, polyester film coated on food flavor in the absorption rate is small can maintain a delicate balance between the tank food of the various components of the deformable to being in a good state for a long time. The three piece cans due to complex production, has been gradually reduced in developed countries, instead of using DRD and cupping DI tank stamping. Japanese steel two cans (DI and TULC) market share has reached 60%.

In recent years, easy to tear off the popularity of foreign countries. The cover is actually by the thickness of 0.07 ~ 0.13MM film secondary cold rolled steel sheet or secondary cold rolling aluminum sheet, through mechanical and heating technology, skillfully seal on the empty cans, use a tear open, certain classes of EPE can withstand high temperature sterilization. From the situation in Europe and the United States, coated aluminum technology than coated iron mature. However, steel easy to tear cover costs only 50% aluminum easy. Therefore, plastic coated iron is easy to tear off the future development of a direction.

The world largest canning group impression holding group (impress holding in Germany has an annual capacity of 14 million for the canned fish factory, with 70% of its using coated aluminum cans. Crown group in France and Italy, a total of four production plants, mainly the production of meat canned (500 million cans / a), also used aluminum coating. Visible, with the development of plastic coated iron technology, in pursuit of profit maximization as the goal of the enterprise will tend to low-cost coated iron instead of high cost of coated aluminum.

At present, the application of plastic coated iron in two cans of China is still in its infancy. With the rapid expansion of the two cans application in the world, has greatly promoted the two cans of market demand in china. At present, the domestic two cans (steel and aluminum) in the annual consumption of about 10 billion or so. With an annual growth rate of 10% to calculate, 5 years after the domestic demand of two cans will reach 16 billion, a net increase of 6 billion. At present, domestic steel two-piece can yield is about 12 million, share of only 12%, insufficient capacity and traditional DL tank production process energy consumption and secondary pollution problem and its inherent disadvantages of flavor makes it impossible to enter the beer market, easy to rust) limits its further development. So it can be predicted that the green environmental protection of coated iron production of two cans of domestic market prospects are very broad.

With the increasingly stringent environmental protection requirements and increasingly scarce resources, recyclable and recycled metal packaging materials for people. According to the European packaging Iron Manufacturing Association reported that in 2003 the European Union 15 countries in the recovery rate of iron and steel has reached 61% (of which Belgium has reached 94%), by 2008, will increase to 70%. So global canning material industry, the canning industry and lid industry that are taking place in revolutionary major changes, secondary cold rolled sheet, coated iron (coated aluminum), tank stamping, drawing special-shaped cans and easy tear cover is slowly becoming the mainstream of the canning industry in the developed countries. The key to these changes is the promotion of the quality of the two cold rolled steel sheet (the progress of the steel making technology) and the development of the film covering technology.