Depending on aluminum foil thickness microns, aluminum foil and composite aluminum foil can be used for various food packaging. Aluminum foil thickness from 10-12 micron is ideal for chocolate and confectionery, while that from 30 to 38µm are used in the dairy industry, for example for packaging desserts, puddings and yogurt. However, for jams and pies, 50-70µm foil is the right choice.
The current trend for aluminum foils is to to be thinner and thinner due to cost reductions. In the field of chocolate packaging, the thickness of the packaging alone has fallen by about 30% over the past 20 years. Currently, the average thickness of chocolate foil is between 7-15µm, which is smaller than the diameter of a human hair.
The largest amount of aluminum in cigarette packaging is aluminum foil lining paper. The aluminum foil lining paper is a composite paper of thin paper and aluminum foil.7 micron and 6 micron aluminum foil are often used. The temper is O with good elongation.
The thickness of aluminum foil used in composite materials can be 7-9 um. At present, light gauge aluminum foil has five to six hundred pinholes per square meter. If its necessary strength is neglected, it can only provide moisture resistance. If its thickness is more than 20μm, it can meet the requirements of no holes and moisture resistance.In actual use, in addition to packaging food and medicine, the thickness selection should be based on different contents.
With the reduction of aluminium foil thickness, the rolling process becomes more and more difficult, and the number of aluminum foil cracks, broken strips, and pinholes increases. The production of high-quality 0.005~0.006mm aluminum foil puts forward more stringent requirements for the hydrogen content of the blank, the content of non-metallic inclusions and the grain size index.
In order to ensure the high purity of the metal, out-of-line refining, degassing and filtration methods are usually adopted in the casting process. Hydrogen remaining in the crystals seriously affects the processing performance of 6 micron aluminium foil, and is one of the main reasons for pinholes in aluminum foil, and its content must be strictly controlled.