Biaxially oriented polypropylene (BOPP) and cast polypropylene (CPP) are both thermoplastic films used for packaging and labeling purposes. They have many similarities in terms of applications, but they also have their differences. In this article, we will explore the characteristics that set BOPP film apart from CPP.
Overview of BOPP and CPP.
BOPP film is a thin and flexible plastic film made from polypropylene polymer. The film is biaxially oriented, meaning it is stretched in two directions, resulting in a film with superior tensile strength and clarity. BOPP films are used for various applications such as flexible packaging, lamination, and labeling due to their excellent moisture resistance and heat sealability.
On the other hand, CPP film is a thermoplastic film made from cast polypropylene. During the manufacturing process, the molten polypropylene is poured onto a casting drum, where it cools and solidifies into a thin film. CPP films are known for their high clarity, gloss, and stiffness. They also have good moisture resistance but offer lesser heat sealability compared to BOPP.
Differences in manufacturing process.
The primary difference between BOPP and CPP lies in their manufacturing process:
BOPP films undergo a biaxial orientation process, which involves stretching the film in two directions to align the molecules uniformly. This process gives BOPP films superior strength, flexibility, and clarity. The biaxial orientation process also helps in improving the moisture barrier and heat sealability of the films.
CPP films are manufactured through a casting process whereby hot molten polypropylene is poured onto a chill roll to form a thin film. During cooling, the molecules align in a random orientation, resulting in a film that is stiff, glossy, and has high clarity. This process makes CPP films less flexible than BOPP. Additionally, CPP films have slightly lesser heat sealability than BOPP films.
Properties and applications.
BOPP films have higher strength, flexibility, and clarity compared to CPP. These films are ideal for flexible packaging applications, such as wrapping food items, confectionery, and pharmaceutical products. They also have excellent moisture and gas barrier properties, making them suitable for extended food preservation. Additionally, BOPP films can be laminated, printed, or metallized, making them versatile for various creative packaging and labeling requirements.
CPP films, on the other hand, have high stiffness, clarity, and good moisture resistance. CPP films are commonly used for labeling applications, such as transparent product labels, and lamination to paperboard for packaging. Due to their higher stiffness, CPP films are also used in packaging applications, such as frozen food bags, snack packs, and stand-up pouches, where the shape needs to be maintained.
Costs and availability.
BOPP films are the most widely available plastic films, and their cost range varies depending on the thickness, clarity, strength, and other factors. In general, BOPP films are considered more economical compared to other packaging materials such as aluminum foil, PET, and PVC. The availability of BOPP films in a wide range of thicknesses makes it suitable for various applications, saving resources and reducing material costs.
CPP films are comparatively higher in cost than BOPP but offer superior clarity and stiffness. CPP films are available in a narrower range of thicknesses compared to BOPP. Hence, CPP is mostly preferred for specific applications that require high stiffness and clarity.
Conclusion.
In summary, BOPP and CPP films are both essential thermoplastic films used for flexible packaging, labeling, and lamination applications. While both films have many similarities, BOPP offers superior strength, flexibility, and clarity. On the other hand, CPP films have higher stiffness and clarity. The choice between BOPP and CPP depends on the packaging requirements and budget of the user.
Contact Us.
If you have any queries regarding BOPP or CPP films or need assistance in selecting the right film for your packaging requirements, please contact us. We will be happy to help you choose the best packaging solutions.
Want more information on bopp, bopp vs vinyl, pearlised bopp film manufacturing process? Feel free to contact us.