Do you understand composite flexible packaging?

1. What is a composite film? What is composite flexible packaging?
Composite film is a material made by laminating two or more layers of different substrates, such as plastic films (polyethylene PE, polypropylene PP, polystyrene, polyvinyl chloride PVC, and polyester PET, etc.), glassine paper, paper, and aluminum foil, etc., to obtain a material with comprehensive properties of each individual material, such as paper/plastic composite film, plastic/plastic composite film, aluminum/plastic composite film, etc.
Composite flexible packaging refers to the combination of two or more layers of composite films, mainly divided into base film, functional film, and heat-sealing adhesive film. The base film mainly provides the basic packaging requirements for the composite film, such as certain mechanical strength, barrier properties, transparency, etc.; the functional film gives the composite film specific functions, such as high barrier properties, gas selectivity permeability, etc.; the heat-sealing adhesive film enables the composite film to be heat-sealed.

2. Applications of composite flexible packaging
Composite flexible packaging is mainly used in food, medicine, cosmetics, beverages, and other product packaging. In recent years, it has maintained rapid development in China.

3. Processing methods of composite flexible packaging
There are several processing methods for plastic film lamination, including dry lamination, wet lamination, extrusion lamination, hot melt lamination, and co-extrusion lamination, etc.
Dry lamination is the most commonly used method in plastic packaging lamination. It uniformly coats a layer of solvent-based adhesive on the first substrate under certain temperature, tension, and speed conditions. After the solvent evaporates and dries through the drying tunnel of the laminating machine, it is laminated with the second substrate (plastic film, paper, or aluminum foil) under hot pressing conditions to form a composite film.
Wet lamination involves coating a layer of adhesive on the surface of the composite substrate (plastic film, aluminum foil). While the adhesive is still wet, it is laminated with other materials (paper, glassine paper) through pressure rolls, and then dried in an oven to become a composite film. Wet lamination has the advantages of simple process operation, less adhesive usage, low cost, high lamination efficiency, and no residual solvent.
Extrusion lamination is the most common method in composite processing. It uses thermoplastic resin as raw material, heats and melts the resin into a mold, flows out as a sheet-like solidified film, immediately laminates with another one or two films, and then cools and solidifies.
Hot melt lamination involves heating and melting the resin, then coating it on the substrate, and immediately laminating it after cooling. The advantages of hot melt lamination are short lamination time, no solvent pollution, and low cost, but its disadvantages are poor heat resistance and transparency.
Multi-layer co-extrusion lamination involves co-extruding multiple resins with different properties through multi-layer extruders, entering the mold to form a film.

4. Prospects of composite flexible packaging
With the cutting of slitting machines, a variety of composite flexible packaging, with its excellent comprehensive performance, is replacing the traditional packaging with an unstoppable trend. Plastic flexible packaging is gaining a higher status in the entire packaging field, especially in the food industry. In recent years, China's flexible packaging industry has developed rapidly, and it has also strongly promoted the progress of the food, daily chemical, and pharmaceutical industries. The progress of these industries, in turn, further stimulates the market demand for plastic flexible packaging films.