Add:Xuanshan Industrial Park, Heshang Town, Xiaoshan District, Hangzhou City, Zhejiang Province, China
Iron boxes, many of which are called iron cans, are made of tinplate as a raw material. They are boxes made of different processes such as welding or stamping and fastening of tinplate. Because it is made of tinplate, it is also called tinplate box.
What is the difference between iron boxes and iron cans? In fact, there is no strict distinction between this point. In general, square and rectangular are called boxes, and rounds are called cans.
Aerosol cans, chemical cans, milk powder cans, and beverage cans are all welded cans. The state has established relevant product standards for products. The principle used is that the material to be welded is pressed by a pair of rotating upper and lower welding wheels with a certain amount of overlap, and the alternating current is low-current and large current, and the contact resistance at the material overlap generates high temperature under the action of a large current to make the material at Plastic melting state. A solder joint is formed under the action of the pressure of the upper and lower electrodes, and one half of the welding current forms a solder joint. The material thus welded is moved at a constant linear velocity by the rotary welding roller to form mutually overlapping points, that is, welds. The solder joint distance is proportional to the weld line speed and inversely proportional to the frequency of the welding current. Solder joint: Under the action of the thermal effect of the current and the mechanical pressure, the weld zone (point) where the two metal sheets are welded together on the metallographic phase, commonly known as the solder joint.
Miscellaneous cans---(non-standard cans, non-welding cans) These cans can be adjusted according to their own products due to their structure and size. Therefore, there is no relevant national standard.
In addition to causing adverse reactions in food, light can also cause changes in proteins and amino acids. However, when vitamin C is exposed to light, it is more likely to cause it to interact with other food ingredients, resulting in a large loss. According to research and analysis, the loss of vitamin C in milk in clear glass bottles is 14 times higher than that in dark bottled milk. It also causes oxidation and odor of milk, as well as cracking of nuclide and methionine, which loses nutritional value. The opacity of the tin can makes the preservation rate of vitamin C the highest.
The barrier properties of packaging containers to air and other volatile gases are important for the preservation of nutrients and sensory qualities. Comparing various juice packaging containers, the oxygen transmission rate of the container directly affects the browning of the juice and the preservation of vitamin C; the metal cans with low oxygen transmission rate, the glass bottle and the aluminum foil, and the preservation of the vitamin C in the carton. It is better, and it is best to use iron cans.
The tin on the inner wall of the tinplate acts on the oxygen remaining in the container during filling, reducing the chance of oxidation of the food ingredients. The reduction of tin has a good preservation effect on the flavor and color of light-colored fruits and juices. Therefore, the juice cans using unpainted iron cans are better preserved than the juice cans of other packaging materials, and the brown change is slight. The flavor quality is better accepted and the shelf life is extended.