Metalized thermal lamination film is a composite flexible packaging material formed by using a special process to coat the surface of the plastic film with an extremely thin layer of metal aluminum, of which the most commonly used processing method is vacuum aluminum plating method, that is, the metal aluminum melts and evaporates at high temperature in a high vacuum state, so that the vapor precipitation of aluminum deposits on the surface of the plastic film, so that the surface of the plastic film has a metallic luster. Because it has both the characteristics of plastic film and metal, it is a cheap and beautiful, excellent performance and practical packaging material.
Below are the performances of it:
1.Appearance
The surface of the metalized pre-coating film should be flat and smooth, without wrinkles or only a small amount of live pleats; no obvious uneven, impurities and stiff blocks; no marks, bubbles, holes and other defects; do not allow obvious glitter, Yin and Yang surface and other phenomena.
2.Thickness of the metalized film
The thickness of the aluminized heat laminating film should be uniform, the thickness deviation of the transverse and longitudinal should be small, and the deviation distribution is more uniform. There is no obvious convex rib on the drum, otherwise it is easy to wrinkle when laminating.
3.Thickness of the aluminum coating
The thickness of the aluminum coating is directly related to the barrier property of the metalized composite film. With the increase of the thickness of the aluminum coating, the transmittance of oxygen, water vapor, light, etc., gradually decreases, and correspondingly, the barrier property of the aluminum plating film is also improved. Therefore, the thickness of the aluminum coating should meet the standard requirements, and the coating should be uniform, otherwise it will not achieve the expected barrier effect.
4.Adhesion
The aluminum coating should have strong adhesion and good firmness, otherwise it is easy to dealuminize and cause quality problems. In the process of high quality vacuum aluminium laminating film, a certain amount of primer glue should be applied on the aluminium surface of the aluminium base film first to improve the bonding force between the aluminium coating and the substrate film, so as to ensure that the aluminium coating is firm and not easy to fall off. Then, the aluminum plating layer should also be coated with a two-component polyurethane adhesive as a top coating to protect the aluminum plating layer from being worn off.
5.Physical and mechanical properties
The metalized thermal laminating film is subject to mechanical force during the composite process, so it is required to have a certain mechanical strength and flexibility, and should have good tensile strength, elongation, tearing strength, impact strength, excellent folding resistance and toughness and other properties to ensure that it is not easy to knead, crumple, fracture and other phenomena during the composite processing.
6.Moisture permeability
Moisture transmittance indicates the permeability of aluminium EVA adhesion film to water vapor under certain conditions, which reflects the moisture resistance of aluminium thermal laminating film to a certain extent. For example, the moisture permeability of 12 um polyester metalized heat lamination film (VMPET) is between 0.3g /㎡·24h ~ 0.6g /㎡·24h (temperature 30℃, relative humidity 90%); The moisture permeability of CPP aluminized film (VMCPP) with a thickness of 25 um is between 1.0g /㎡·24h and 1.5g /㎡·24h (temperature 30℃, relative humidity 90%).
7.Oxygen permeability
Oxygen permeability represents the amount of oxygen penetration of the aluminum thermal lamination film under certain conditions, which reflects the size of the barrier of the metalized thermal lamination film to oxygen, such as the oxygen permeability of the polyester aluminium pre-coating film with a thickness of 25 um is about 1.24 ml/㎡·24h (temperature 23℃, relative humidity is 90%).
8.The size of the surface tension
In order to make the ink and composite adhesive have good wettability and adhesion on the surface of the aluminium composite film, it is required that the surface tension of the metalized pre-coated film should reach a certain standard, otherwise it will affect the adhesion and adhesion of the ink and adhesive on the surface, thus affecting the quality of the printed matter and composite products. For example, the surface tension of the polyester aluminium thermal lamination film (VMPET) is required to reach more than 45 dynes, at least 42 dynes.
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Post time: Aug-08-2023