Aluminum foil, though very thin, has the following advantages as a packaging material:
(1) Light weight, conducive to reducing transport costs.
(2) Good isolation and shading. It is moisture-proof, air-tight and fragrance-preserving. It can prevent moisture absorption, oxidation and volatilization of packaging.
(3) It has good heat resistance, stable shape at high and low temperatures, and can be used as a container for baking.
(4) Strong protection: the packaging is not easily damaged by bacteria, fungi and insects.
(5) Good reflection and luster of light. It has high reflectivity to heat and light, and its reflectivity is 83%~85%. Therefore, the exhibition effect is excellent.
(6) It has good mechanical properties and can be used in automatic packaging machinery.
(7) Good moulding and embossing performance in secondary processing.
(8) Good printing and composite adaptability. Easy to colour, easy to fit with paper, plastic, etc.
(9) Non-toxic, not easy to produce public hazards.
Although aluminium foil has the above advantages, it is seldom used alone because of its low strength, poor tear resistance, easy to crack in folding, acid-alkali resistance, and inability to heat bond and seal. Most aluminium foil is processed with plastic film, paper and other materials, and used in the form of composite materials. This not only keeps the excellent performance of aluminum foil, but also makes up for the shortcomings of some packaging properties of aluminum foil. The thickness of aluminium foil used in composite state can be reduced to 0.007? 0.009 mm. Compared with the composite material without aluminium foil, the composite material containing aluminium foil has better barrier, especially shading, and can meet the requirements of vacuum, sterility and nitrogen filling packaging technology. It is a new packaging material with strong adaptability and wide application. It can be used not only as soft packaging material, but also as semi-hard and hard packaging material. It has been widely used in food packaging and has replaced some metal cans. For example, in order to protect against the hazards caused by Ik waste bottles and cans, the tin-plated tin cans and glass bottle beverage containers in the past have been replaced by vertical aluminum foil bags (juice) and paper packaging containers (with aluminum foil inside).