The aluminum foil of the aluminum foil composite bag is made by high-purity (purity of 99.5% or more) electrolytic aluminum after multiple rolling, and the application of the aluminum foil material in the composite flexible packaging has the following outstanding advantages:
1. The appearance is bright and beautiful, with silver-white metallic luster and good reflectivity, giving a feeling of luxury, which is not available in plastic film. Therefore, the use of aluminum foil in the packaging of goods can be used to beautify the product and improve the grade of the product.
2, high barrier and shading. Compared with paper and plastic film, aluminum foil has excellent barrier properties such as moisture resistance, gas barrier properties, light blocking properties and aroma retention due to its highly dense metal crystal structure. When aluminum foil is combined with paper, film, etc., it can almost completely block any
The passage of gas, water vapor and light can effectively protect the contents of the package and prevent the contents from spoiling and oxidizing due to moisture absorption and oxidation, thereby greatly extending the shelf life and shelf life of the package contents.
3, aluminum foil natural starch based on the fast heat transfer rate, and high temperature resistance, so it has been widely used in cooking packaging.
4, aluminum is a light weight metal, the use of aluminum foil for packaging can save and reduce transportation costs.
5, can be recycled and reused, so as to reduce energy consumption; and non-toxic, odorless / tasteless, will not affect the flavor of the package contents.
Due to the outstanding advantages of the above aspects, aluminum foil has become a widely used packaging material in the flexible packaging industry.
Second, the main performance indicators of aluminum foil materials
The thickness of the foil pouch is a basic and very important physics, l, energy. The thickness of aluminum foil has a certain relationship with its barrier property. As the thickness of aluminum foil increases, its transmittance to oxygen, water vapor, light, etc. is gradually reduced, and accordingly, the barrier property is higher. The thickness of the aluminum foil used in the flexible packaging of the composite aluminum foil bag is usually between 7 and 9 lLm. In practical applications, the aluminum foil of a suitable thickness should be selected according to the difference in content and performance requirements, otherwise it will not be achieved. The expected barrier effect (too thin) or an increase in cost (too thick).
In addition, it should be noted that the thickness of the aluminum foil must be uniform, and if the thickness of the aluminum foil is uneven, problems easily occur in production. First of all, the thickness of the aluminum foil is inconsistent, and it is difficult to uniformly coat the adhesive during the lamination process of the aluminum foil bag, thereby affecting the composite strength of the aluminum foil and the plastic film; secondly, the thickness of the aluminum foil is thin.
Inconsistent, the material roll is loose on one side, and the roll phenomenon of the material roll will appear in the compounding process. After the tension is applied to the rewinding and unwinding, the foil is easily broken, which is very unfavorable for the smooth progress of the composite process.
2, moisture permeability
The moisture permeability refers to the amount of water vapor permeated by the aluminum foil under certain conditions, which reflects the corrosion resistance of the aluminum foil to a certain extent. The relationship between the thickness of the foil pouch and its moisture permeability can be seen
3, the number of pinholes
In the calender manufacturing process of aluminum foil, if the purity of aluminum is not high enough, and/or the shadow of dust in the surrounding air during calendering, when the aluminum foil is calendered to a thickness of 10 1 lm or less, pinholes and needles are often present. The number of holes and the size of the pinhole diameter depend on the amount of dust and the size of the dust particles. Due to the existence of pinholes, the barrier properties of aluminum foil may be seriously affected. For example, in the cooking bag where the lye foil is used as the intermediate layer material, the presence of a large number of pinholes easily penetrates oxygen, water vapor, and light, and The quality of the packaged foods has a negative impact on the food, and even causes spoilage of the food. Therefore, the number of pinholes of the aluminum foil is required to be as small as possible, and the aperture should be as small as possible. In general, the number of pinholes of a 71 lm thick aluminum foil should be less than 50 holes/m2, and the number of pinholes of a 9 Dlm thick aluminum foil should be less than 30 holes/m2. In order to reduce the number of pinholes in aluminum foil and improve its barrier properties, in aluminum foil
High-purity aluminum raw materials must be used in the manufacturing process, and the purity is required to be at least 99.5%. At the same time, the environment in the rolling workshop should be kept clean and free of dust, and the influence of dust particles on the quality of the aluminum foil should be prevented.
4, surface cleanliness
When the aluminum foil bag is compounded, the degree of surface cleanliness has a decisive influence on the composite strength. If the surface cleanness of the aluminum foil bag is relatively poor and the oil remains, the composite strength is relatively poor. In the calendering process of aluminum foil, a large amount of lubricating oil is used and the rolling is good.
The aluminum foil is cleaned with an organic solvent acetone before winding, and the lubricating oil used for the pressure reduction is cleaned. In addition, the aluminum foil used in the aluminum foil bag is subjected to a high-temperature annealing treatment under a high vacuum (0.0133 Pa) to leave residual lubrication on the surface of the aluminum foil; This
Although it is beneficial to the improvement of the surface cleanliness of the aluminum foil, it is inevitable that a small amount of oil will remain, and the residual amount of the oil determines the surface cleanliness. The surface cleanliness standards of the aluminum foil are divided into A, B, and C. Five levels of D, E, of which A is the best cleanliness, almost no oil; B is the second, and so on. The method for judging the cleanliness level of aluminum foil surface requires high surface cleanness of aluminum foil in composite flexible packaging. Generally, it should reach grade B or above, and there is no uneven oil pollution. The composite adhesive can have good surface wetting. Role, otherwise it will affect the composite quality of the product. Therefore, in the actual ± production should bear in mind the strict quality control, be sure to do a good job in the inspection of aluminum foil cleanliness, this can not be ignored.
Aluminum foil bag is the perfect combination of metal and plastic / just and soft, is irreplaceable in other bags, aluminum foil bag is a star in composite flexible packaging.
HTMM GROUP CO.,LTD exporting Aluminium foil with good quality ans service 10 years.
Alloy : 1235/8079
Temper : HO
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