How Bopp Films are Produced?

How Bopp Films are Produced?

Bopp films have become a popular packaging material for several industries due to their excellent strength, clarity, and durability. Bopp stands for Biaxially-oriented polypropylene, which is a thermoplastic polymer that is widely used for flexible packaging. In this article, we will explain how Bopp films are produced and their unique properties.

1. Extrusion.

The Bopp film production process begins with the extrusion of Bopp resins. The resin is fed into an extruder, where it is melted under high temperature and pressure. The hot molten material is then extruded through a flat die, which forms a thin film of Bopp. The thickness of the Bopp film is determined by the size of the gap between the die lips, and the speed of the cooling process.

2. Orientation.

Bopp films are biaxially oriented, which means that they are stretched in two directions – the machine direction (MD) and the transverse direction (TD). The orientation process involves stretching the film by passing it through a series of rollers, which exert tension in the MD and TD directions. This stretching process improves the mechanical properties of the film, such as tensile strength, tear resistance, and clarity.

3. Corona Treatment.

Corona treatment is a surface modification process that involves exposing the Bopp film to a high-voltage electrical discharge. This treatment improves the surface tension of the film, which enhances its printability and adhesion to other materials. The corona treatment also removes any contaminants from the film surface, which can affect the quality of the print.

4. Metallization.

Metallization is a process that involves depositing a thin layer of metal, usually aluminum, on the surface of the Bopp film. The metal layer provides a barrier to moisture and oxygen, which improves the shelf life and freshness of the packaged product. Metallized Bopp films are widely used for snack packaging, coffee bags, and other products that require a long shelf life.

5. Coating.

Coating is a process that involves applying a layer of adhesive or functional coating on the surface of the Bopp film. The coating enhances the functionality of the film, such as improving its anti-fog properties, heat-sealing, or anti-static properties. Coated Bopp films are widely used for food packaging, medical packaging, and industrial applications.

In conclusion, Bopp film production involves several steps, including extrusion, orientation, corona treatment, metallization, and coating. Each of these processes contributes to the unique properties of Bopp films, such as strength, clarity, printability, and barrier properties. Bopp films are widely used in the packaging industry and have become an essential material for several applications.

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