Composite film

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Composite film is a multilayer packaging foil from the flexible packaging are made. The individual film layers are usually extruded or laminated or laminated . The packaging is mainly used in the food industry .

construction

The structure of this composite film consists of individual layers, which are specified for the respective application. With a solvent-free or solvent-based adhesive lamination, the individual mono-foils are built into a composite. Also, extrusion lamination or extrusion coating - albeit less frequently these days - is still used.

Carrier layers

The carrier film is the film layer that is used for printing the film. The composite film can be equipped with an additional barrier layer if the carrier film does not already have a sufficient inherent barrier. The additional barrier layer can then be introduced into the sealing film. Usually EVOH - embedded in PE - is used for this.

Carrier foils can also be equipped with small, medium and higher barriers. In the case of a 2-layer composite, one speaks of duplex and a 3-layer of triplex composite films. The laminated composite films are used in thermoforming as an upper film and less often as a lower film. Also as a tray sealing film for so-called tray sealer ( sealed tray or shell ) composite films are used. Composite films for tubular bag machines - horizontal and vertical have been used for many years, namely as tubular bag films.

The composite films have different properties depending on the carrier. The foils can consist of:

Metallized foils

Metallized foils, e.g. B. on the basis of polypropylenes , arise by a carrier film with a very thin layer (pure) aluminum is vaporized in a vacuum . This process is based on physical vapor deposition . This gives the foils a metallic sheen. They can be concealed against other foils . This treatment is done not least because of the optical effect. On the other hand, the metallized version offers protection from light and oxygen.

In addition to the food packaging sector, metallized films can also be found among others. a. as rescue blankets or in fashion use.

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  1. Properties and illustrations