Canned food nutrition, safety, convenience, and should be the most convenient food. Tinplate cans in the past few decades has been full cover, glass jars victory of the Soviet-style bottle, consumers spread "canned delicious, mouth difficult to open. This is a persistent problem. Consumers are very convenient, but also seriously affected the development of the canning industry. Actively promote the canning industry, tin cans with easy-open lid, glass jars with twist caps. More than a dozen years ago, a large number of easy-open lid is rice pudding, canned, Cans tank bottom tinplate easy open lid made of aluminum alloy, with a small plastic spoon, eating is very convenient, consumers are very satisfied, now canned rice pudding annual sales about 30 million tons.
However, not all canned varieties can be modeled rice pudding canned can be used aluminum easy-open lid. A few years ago, Guangdong has a canned food factory production of canned tomato juice, modeled on the bottom of the tank of rice pudding, canned cans using tinplate lid aluminum alloy easy-open lid, adding 0.5% salt (Nacl), the contents of calculating the chlorine content of 303 mg of the / kg storage a few months, in easy-open lid at the rivets and crossed at the drain tank, and was forced to stop production.
The tank bottom of the container body after the use of tinplate, such as can lids with aluminum alloy, food canning, the formation of micro-battery, bi-metal reaction, aluminum as the anode, and the tin as a cathode when the cathode area than the anode area, the anode occurs at the local deep pitting until perforation. Taiwanese pop canned coconut milk beverage Taiwan reported in the literature, a few years ago, the use of aluminum easy-open lid, cans, tinplate tank bottom, chloride ion concentration of 440 ~ 1492mg/kg contents, PH = 4.4 to 4.6, Apple acid. Canning early corrosion ingredients (malic acid, chloride ion) to penetrate the paint film, the electrochemical reaction. The coating film is a cathode, the paint film by the membrane damage at the exposed tin, iron as the anode, until a considerable area of the tin, iron is exposed, due to coating damage at the exposed aluminum string together, forming a micro battery with aluminum EOE The bimetallic response. At this point, aluminum anode corrosion was dissolved, plus the presence of chloride ion in the contents, prompted the development of the corrosion reaction is accelerated to cause the aluminum alloy EOE rivets, the scribe at the perforation.
Reports that some high-acid foods, chlorine ions than 100mg/kg, canned meat and aquatic vegetables (add salt, sodium chloride) using tinplate cans, the bottom of the tank, the lid should not use aluminum alloy material, should be used tinplate easy to pull cover, in order to avoid the the bimetallic electrochemical reaction perforation.
The main production of tinplate easy-open lid Zhe Jiang Changhong system covered Limited, easy open end Industry Company in Yiwu, Shantou Shanzhang Hardware Craft Factory new factory. Is expected that this year the production of tinplate easy-open lid about 1.2 billion, of which exports about 100 million, to provide domestic canning industry uses about 1.1 billion, roughly 440,000 tons of canned food can be supporting.
China this year is expected to produce more than 3 million tons of canned food, in addition to part of the use of glass jars. Therefore, the future prospects are very broad in tinplate easy open lid.
The canning industry on the international situation is also an upward trend tinplate easy-open lid. According to the information, in Europe with easy-open lid canned canned food has more than 60%; United States is only 25%, Heing company in 1985 and has produced 400,000 tons of easy-open lid canned food, reported recently compbell.s ( Campbell soups canned) production of canned soups have been using the easy-open lid.
Quality of domestic production tinplate easy-open lid, than in previous years have been greatly improved and enhanced, but there are still some technical problems. Easy-open lid of the basic requirements of quality, should be sealed and easy to pull. I came across tinplate easy-open lid frequently with pliers to help, in order to fully open, sometimes the rivets off, but to continue to use the can opener. The shaped cans easy-open lid opened more difficult. Two production tinplate easy-open lid plant equipment are imported brand-name products, should be no problem. I think the key is to use tinplate thickness, hardness and mold problems. Therefore, enterprises should also organize technical force, well-researched, effective measures, and constantly improve the quality of play to the advantages of easy-open lid and its due role.