PennPac offers a wide range of Biaxially Oriented Polypropylene (BOPP) films for food packaging, printing and laminating, pressure-sensitive labels, and industrial applications. BOPP film is stretched in both machine and transverse directions which results in increased toughness and stiffness.

What is BOPP packaging film and how is it made?

1. Polypropylene Base: BOPP is derived from polypropylene, a versatile polymer known for its excellent chemical resistance, high melting point, and low density. Polypropylene is a type of plastic that can be melted down and reshaped multiple times without significant degradation in its properties.
2. Extrusion: The manufacturing process of BOPP begins with the extrusion of molten polypropylene resin. In this step, polypropylene pellets are melted and formed into a flat sheet or film using an extrusion process. The thickness of this initial film can be controlled based on the desired application.
3. Biaxial Orientation: BOPP stands out due to its biaxial orientation, which involves stretching the film simultaneously in both the machine direction (MD) and the transverse direction (TD). This elongation process aligns the polymer molecules in two directions, resulting in enhanced mechanical properties such as tensile strength, stiffness, and clarity. Biaxial orientation also reduces the film’s thickness while maintaining or improving its strength. This limits propagation as well.
4. Orientation Stage: After the initial extrusion, the polypropylene film is passed through a series of heated rollers, where it is stretched mechanically in both the machine direction and the transverse direction. The extent of stretching can be controlled to achieve specific properties tailored to the intended application.
5. Heat Setting: Following the stretching process, the film is heat-set to stabilize its molecular orientation. Heat setting involves heating the stretched film to a specific temperature below its melting point and then rapidly cooling it. This step helps to lock in the orientation of the polymer molecules, ensuring that the film retains its mechanical properties over time.
6. Trimming and Winding: Once the biaxially oriented polypropylene film has been heat-set, it is trimmed to the desired width and wound into rolls for further processing or packaging. The trimmed edges are often recycled back into the manufacturing process to minimize waste. Read about PIR and PCR here.
7. Surface Treatment (Optional): Depending on the intended application, the BOPP film may undergo surface treatment to enhance adhesion or printability. Common surface treatment methods include corona treatment or flame treatment, which modify the surface properties of the film to improve ink adhesion or lamination performance.

BOPP films provide great clarity, improved oil, grease and chemical resistance, and enhanced barrier properties to water vapor and oxygen. They also have low antistatic properties – helping to extend product shelf life and serve as a moisture and oxygen barrier. The films are also recyclable and eco-friendly.

Our BOPP films are manufactured with sustainability in mind and are cost-effective. PennPac’s BOPP films are used in a variety of modern flexible food packaging applications such as baked goods, snack foods, confections, frozen foods, pet food and treats, and more.