The amount of aluminum used is reduced significantly. It save energy and materials, and reduce costs.
(1) The thickness of the aluminum foil for lamination is mostly 7 to 9 μm, and the thickness of the aluminum layer of the metallized film is about 0.05 n. The aluminum consumption is about 1/140 to 1/180 of the aluminum foil. And the production speed can be up to 450m / min.
(2) It has excellent folding resistance and good toughness. Pinholes and cracks are rare. So the barrier property against oxygen , water vapor, odor, light, etc. is improved.
(3) It has excellent metallic luster, and the light reflectance can reach 97%. It can be processed by coating to form a color film and this is beyond the reach of aluminum foil for such decorative effect.
(4) Can be partially metallized with a shield to obtain any pattern or transparent window to see the contents.
(5) The aluminum layer has good electrical conductivity and can eliminate the electrostatic effect; Its sealing performance is good, especially when packaging powdery products, it will not pollute the sealing part.
(6) It has good adaptability to post-processing such as printing and compounding.
The above characteristics make the metallised film a new type of composite film with excellent performance, glossy appearance and economy , which has replaced the aluminum foil composite material in many aspects.
It is mainly used for vacuum packaging of flavor foods and agricultural products, as well as packaging of medicines, cosmetics and cigarettes. In addition, also widely be used as bronzing materials and trademark label materials in printing.
To check the adhesion of the aluminum layer of metallised film, first we confirm the aluminum side.
The usual practical method is to gently tap the front and back sides of the film with your fingers, and the film surface generally does not have obvious scratches. The aluminum layer will have obvious scratches due to the friction of the external force.
The usual test method of Aluminium adhesion is the tape test method, which is to apply a 3M tape with a length of 15-20cm and a width of 0.5-1 inch to the aluminum layer of the film and flatten it, then uniform. The tape was peeled off, and the area where the aluminum layer was peeled off was observed and estimated. The area which was less than 10% is grade one, less than 30% is grade two and more than 30% is grade three.
The tape test method is only a qualitative test method and is only suitable for general qualitative comparison. If the adhesion fastness of the aluminum layer exceeds the adhesive force of the tape, the difference in adhesion fastness of the aluminum layer is not obtained respectively.
Nowadays, the commonly used quantitative detection method is to heat-sealing with an EAA film (thickness 20-50um, AA content is generally about 9%) and an aluminum layer of the film at a certain temperature, pressure and time. After heat sealing, the sample was cut to a width of 15 mm, and a peeling test was performed on a tensile tester to observe and record the peeling force and the area where the aluminum coating layer was peeled off.
The most widely used metallized films are mainly polyester metallized film (VMPET) and CPP metallised film (VMCPP).
The surface of the film is coated with aluminum to prevent light and ultraviolet radiation, which not only prolongs the shelf life of the content, but also increases the brightness of the film. It replaces the aluminum foil to a certain extent, and has the advantages of low cost, good appearance and good barrier property.
Therefore, the application of metallised film in composite packaging is very extensive, and currently it is mainly used in dry and puffed food packaging such as biscuits and on the outer packaging of some medicines and cosmetics.